MEM variable capacitors can be implemented in both analog and digital configurations. Analog variable capacitors have the advantage that they can be tuned to any value in their capacitance range. However, they are subject to capacitance variations resulting from voltage fluctuations on the control line. Further, the tuning range of analog variable capacitors is typically limited by the pull-in phenomena associated with electrostatic parallel-plate actuators. Digital MEM variable capacitors have been demonstrated using switching networks with very high capacitance ratios (>10). Unfortunately, the switches introduce a small resistance that limits the ultimate Quality (Q) values of the devices. Further, the size of a switching network and multiple capacitors limits the maximum frequency for which the device can operate. Digital MEM variable capacitors have also been implemented using mechanical standoffs to create capacitors with fixed up and down states. In these devices, multiple mechanical structures are used to create multiple digital states. These devices are controlled using individual control lines with one control line designated to each state. This requires a large number of control lines for each digital capacitor and limits the application of the devices in large numbers.
It would, therefore, be desirable to overcome the aforesaid and other disadvantages.